A conventional pepper grinder can also be rotated counterclockwise, and its counterclockwise rotation can cause grinding teeth in a grinding wheel and a grinding cylinder to harm each other, and if worse, a small bit of metal tooth broken down from them can mix with ground pepper to go into food.
One more disadvantage that a conventional pepper grinder has is that clockwise manual rotation of a rotatable cap has to be repeated in grinding pepper, so a user has to move his hand repeatedly and rotate the cap to a largest angle and then release his hand to grip the cap again.